Allow php sessions to carry over to subdomains

Question

I use php sessions (not cookies, except for session id cookie) for all user data, and when a user goes to their profile user.mydomain.com they are immediately \"logged out\"

Answer 1

Try This:

session_start(); 

$sessionId =  session_id();

logged the user. When user will switch to other subdomain sent the session id in the URL like this user.mydomain.com/?id=$sessionId

$sessionId =  $_GET['id'];

session_start($sessionId); 

Now the user will get all the session values and stay logged in.